PPC: [runtime] Throw exception for derived constructors in correct context.

Port c86f1897

Original commit message:
    When derived constructors return a non-object (or not undefined) we
    currently throw an exception directly in the callee context. This was
    achieved by desugaring the return statement for derived classes. To
    be spec compliamnt a separate ConstructStubForDerived is introduced.
    Instead of trowing directly, the desugared return statement inside
    a derived constructor only returns an integer to indicate an incompatible
    result.

R=cbruni@chromium.org, joransiu@ca.ibm.com, jyan@ca.ibm.com, michael_dawson@ca.ibm.com
BUG=v8:4509
LOG=n

Review URL: https://codereview.chromium.org/1595593002

Cr-Commit-Position: refs/heads/master@{#33341}

src/ppc/builtins-ppc.cc

@@ -421,7 +421,8 @@ void Builtins::Generate_InOptimizationQueue(MacroAssembler* masm) {
 
 static void Generate_JSConstructStubHelper(MacroAssembler* masm,
                                            bool is_api_function,
-                                           bool create_implicit_receiver) {
+                                           bool create_implicit_receiver,
+                                           bool check_derived_construct) {
   // ----------- S t a t e -------------
   //  -- r3     : number of arguments
   //  -- r4     : constructor function
@@ -680,6 +681,19 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
     // Leave construct frame.
   }
 
+  // ES6 9.2.2. Step 13+
+  // Check that the result is not a Smi, indicating that the constructor result
+  // from a derived class is neither undefined nor an Object.
+  if (check_derived_construct) {
+    Label dont_throw;
+    __ JumpIfNotSmi(r3, &dont_throw);
+    {
+      FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+      __ CallRuntime(Runtime::kThrowDerivedConstructorReturnedNonObject);
+    }
+    __ bind(&dont_throw);
+  }
+
   __ SmiToPtrArrayOffset(r4, r4);
   __ add(sp, sp, r4);
   __ addi(sp, sp, Operand(kPointerSize));
@@ -691,23 +705,23 @@ static void Generate_JSConstructStubHelper(MacroAssembler* masm,
 
 
 void Builtins::Generate_JSConstructStubGeneric(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, true);
+  Generate_JSConstructStubHelper(masm, false, true, false);
 }
 
 
 void Builtins::Generate_JSConstructStubApi(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, true, true);
+  Generate_JSConstructStubHelper(masm, true, true, false);
 }
 
 
 void Builtins::Generate_JSBuiltinsConstructStub(MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, false);
+  Generate_JSConstructStubHelper(masm, false, false, false);
 }
 
 
 void Builtins::Generate_JSBuiltinsConstructStubForDerived(
     MacroAssembler* masm) {
-  Generate_JSConstructStubHelper(masm, false, false);
+  Generate_JSConstructStubHelper(masm, false, false, true);
 }